We all know that life needs to go hand in hand with our athletic pursuits. External stressors from school, college, work, and family (and a host of other things) play a major role in our response to training. Often, as athletes and coaches, we don’t account for these stressors and are left asking questions such as “why did that session feel so difficult compared to the sessions on the weekend?” and “why did I underperform in this race?”
By taking a look at the finer details, we often find out that it was, in fact, both mismanaging external stress and our training load that caused the issue. This study by Filipas, Pollastri, and Torre addressed this premise to see if there is any truth in it.
Aim of the study
The study aimed to investigate the effect of a mentally demanding inhibitory task on time trial performance in sub-elite under-23 cyclists. Simply put, what is the effect of doing a mentally draining task shortly before a training session?
How did they do this?
Ten under-23 road cyclists (20±1.2 yr / 66.1±7.6 kg) voluntarily participated in the study. These athletes were classified as well-trained: VO2max 69.0±4.4 mL-min-1.kg-1, peak power 380±39 W, > four training sessions per week, > 300 km per week, > three years of cycling experience, etc.
The authors used a randomized counterbalanced crossover design, which means participants were randomly assigned and balanced, and each experienced the “intervention” after adequate rest.
The participants visited the lab on four separate occasions, which looked a little something like this:
Visit 1: Weight and height + familiarization with the tasks
Visit 2: A VO2max test (incremental ramp to exhaustion)
Visits 3 & 4: A performance with and without (control task) a mentally demanding task beforehand
In terms of the mental and physical tasks themselves, the authors used the Stroop Task, psychological questionnaires, and a 30-minute cycling time trial during which they measured power output, heart rate, cadence, and RPE. Blood lactate and heart rate variability (HRV) was measured in specific increments afterwards (a simple marker of recovery processes).
What was the outcome?
Psychological responses to the Stroop Task included a decrease in vigour and an increase in fatigue. There was a significantly higher mental demand, effort, and frustration level when compared with the control. Long story short, the task was enough to elicit some form of mental fatigue.
So, how did this affect time trial performance?
The power output recorded after the Stroop Task compared to control conditions was lower (overall mean Stroop Task: 287 ± 23 W; overall mean control: 295 ± 23 W), and cadence was also lower after the Stroop Task compared to the control (100 ± 7 rpm versus 102 ± 6 rpm). There appeared to be no significant differences in RPE or heart rate during the time trial.
There was no significant difference during the period afterwards where blood lactate and HRV were measured.
Conclusions and takeaway points
We see a significant difference in both power and cadence after a mentally demanding task. While the decrease (in absolute terms) is not massive, it could be the difference between finishing a specific interval and failing on one. This may highlight the importance of adjusting training intensity after a stressful day or stressful task.
It also suggests that mentally demanding tasks should be avoided before competition. It would have been interesting to rate the participant’s “enjoyment” of the time trial to see if mental fatigue induced training monotony symptoms.
Interestingly, the authors highlight another study on recreational and elite-level athletes  that shows their decrease in performance to be 5.8 percent and 0.9 percent respectively. These sub-elite athletes had a decrease of 2.8 percent. It’s fair to draw a conclusion that the more elite you are as an athlete, the less “stress” affects your performance.
In summary, we can conclude that mentally draining tasks do, in fact, affect performance. We should be aware of stressors in our lives as athletes and coaches, and plan for them in training while aiming to limit them during competition.
Featured Paper: Riva, N., La Torre, A., Gallo, G., Pollastri, L., & Filipas, L. (2017). Mental fatigue impairs time-trial performance in under-23 cyclists. In Congresso nazionale SISMES (Vol. 13, No. suppl. 1, pp. S35-S36). Springer.
- Martin K, Staiano W, Menaspà P, Hennessey T, Marcora S, Keegan R, Thompson KG, Martin D, Halson S, Rattray B. Superior inhibitory control and resistance to mental fatigue in professional road cyclists. PloS One. 2016; 11(7)